The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of 14 000 F and G dwarfs
We present and discuss new determinations of metallicity, rotation, age,kinematics, and Galactic orbits for a complete, magnitude-limited, andkinematically unbiased sample of 16 682 nearby F and G dwarf stars. Our63 000 new, accurate radial-velocity observations for nearly 13 500stars allow identification of most of the binary stars in the sampleand, together with published uvbyβ photometry, Hipparcosparallaxes, Tycho-2 proper motions, and a few earlier radial velocities,complete the kinematic information for 14 139 stars. These high-qualityvelocity data are supplemented by effective temperatures andmetallicities newly derived from recent and/or revised calibrations. Theremaining stars either lack Hipparcos data or have fast rotation. Amajor effort has been devoted to the determination of new isochrone agesfor all stars for which this is possible. Particular attention has beengiven to a realistic treatment of statistical biases and errorestimates, as standard techniques tend to underestimate these effectsand introduce spurious features in the age distributions. Our ages agreewell with those by Edvardsson et al. (\cite{edv93}), despite severalastrophysical and computational improvements since then. We demonstrate,however, how strong observational and theoretical biases cause thedistribution of the observed ages to be very different from that of thetrue age distribution of the sample. Among the many basic relations ofthe Galactic disk that can be reinvestigated from the data presentedhere, we revisit the metallicity distribution of the G dwarfs and theage-metallicity, age-velocity, and metallicity-velocity relations of theSolar neighbourhood. Our first results confirm the lack of metal-poor Gdwarfs relative to closed-box model predictions (the ``G dwarfproblem''), the existence of radial metallicity gradients in the disk,the small change in mean metallicity of the thin disk since itsformation and the substantial scatter in metallicity at all ages, andthe continuing kinematic heating of the thin disk with an efficiencyconsistent with that expected for a combination of spiral arms and giantmolecular clouds. Distinct features in the distribution of the Vcomponent of the space motion are extended in age and metallicity,corresponding to the effects of stochastic spiral waves rather thanclassical moving groups, and may complicate the identification ofthick-disk stars from kinematic criteria. More advanced analyses of thisrich material will require careful simulations of the selection criteriafor the sample and the distribution of observational errors.Based on observations made with the Danish 1.5-m telescope at ESO, LaSilla, Chile, and with the Swiss 1-m telescope at Observatoire deHaute-Provence, France.Complete Tables 1 and 2 are only available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/989
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UBV (RI)c observations of Johnson's standard sequence in IC 4665.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996MNRAS.282..313M&db_key=AST
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ICCD speckle observations of binary stars. IX - A duplicity survey of the Pleiades, Praesepe, and IC 4665 clusters
Multiplicity of stars within clusters is a well-studied phenomenon.However, recent survey work done on the Hyades by Mason et al. (1993)would seem to indicate that even in the most often studied clusters,there may be binaries yet undiscovered. In order to expand the sample ofcluster binaries with potentially short-period visual orbits, a specklesurvey of 45 Pleiades, 54 Praesepe, and 22 IC 4665 bright stars (V isless than 10) for possible multiplicity was conducted at the KPNO 4 mMayall telescope between 1987 October and 1991 November. Of these, threenew binaries have been discovered: one in the Pleiades where the newcomponent may be spectroscopic, another in Praesepe which has beenconfirmed from examinations of archival observations and also has beenresolved by occultation, and the third in IC 4665. Continued study ofthese new binary stars could further refine the cluster distance modulias well as the cluster mass-luminosity relations.
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V728 Herculis - an active W Ursae Majoris system of F spectral type
Observations made of the short-period eclipsing binary system V728 Herusing a photoelectric telescope on four nights in June 1988 at LowellObservatory are presented. Three times of minimum light were revealed byobservations covering the eclipse portions of the light curves. A periodstudy covering 80 years of observations indicates that a drastic periodincrease may have recently occurred, while indications such as apossible reversal of eclipse depths may suggest that V728 Her ismagnetically active. Standard magnitudes derived for V728 Her and forcomparison and check stars indicate that V728 Her is approximately ofspectral type F3 while the comparison and check stars are K type. Apreliminary light-curve solution indicates that the system consists oftwo nearly equal temperature components in the spectral class F3 to F4in contact with a substantial fillout of near 20 percent and a massratio of about 0.4. This degree of contact is supported by the positionof V728 Her on the period, color plane of Eggen. The period increase mayindicate a mass exchange from the secondary to the primary component ora catastrophic angular-momentum loss due to an episode of massivestellar wind expulsion along lines of a corotating magnetic field.
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B and V light curves of TY Bootis
The short-period eclipsing binary system TY Boo was observed on fiveconsecutive nights with facilities at Lowell Observatory. Theobservations covering the eclipse portions of the light curves yieldedfive epochs of minimum light. The light curves, defined by 348observations with the B filter and 353 with the V filter, are of the WUrsae Majoris type and are symmetric. The system becomes redder duringeach eclipse with a momentary dereddening at phase 0.0.
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UBV Photometry of Equatorial Stars
Not Available
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Observations of new southern spectroscopic binaries with the objective prism method
The occurrence of variable radial velocities in the catalog of Gieseking(1980) is investigated by a statistical analysis of the observed errorfrequency distribution. It is shown that the homogeneity of theobservation material and the large number of observations per objectallow a reliable identification of variable radial velocities. Thus, ina sample of 303 stars with spectral types between B3 and F5, a 20%frequency of variable radial velocities is found. If the radial velocityvariations are assumed to be entirely due to binary motion, this resultis equivalent to a 20% frequency of binary systems with separationsgenerally less than 1 AU.
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Relative radial velocities from objective prism spectra in the region of nine southern open star clusters and a star field at Eta Carinae
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&AS...41..245G&db_key=AST
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Four-color and H beta photometry for open clusters.8 IC 4665.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972AJ.....77..862C&db_key=AST
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Membership of the open cluster IC 4665.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972A&A....17..193S&db_key=AST
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A photometric study of the open cluster IC 4665
Not Available
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Distances of five open cluster near Eta Carinae
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1965MNRAS.129..237S&db_key=AST
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The Galactic Cluster IC 4665.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1964ApJ...139.1139A&db_key=AST
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An OB association in the region of RS Puppis
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1963MNRAS.127...71W&db_key=AST
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Positions and proper motions of stars in the region of the galactic cluster IC 4665.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955AJ.....60..384V&db_key=AST
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The galactic cluster IC 4665.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955AJ.....60..365H&db_key=AST
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The Standard Region Near IC 4665.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1954ApJ...119..181J&db_key=AST
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Untersuchung der offenen Sternhaufen IC 4665, NGC 6633, IC 4756
Not Available
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Relative photographic positions of 31 stars in the open cluster IC 4665
Not Available
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Photometrische Vermessung der Sternhaufen NGC 752 und IC 4665
Not Available
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